1. FIELD OF THE INVENTION
This invention relates to a disposable spray dispensing assembly adapted for detachable connection to a source of pressurized air for applying adhesives, coatings, sealants, solvents, penetrants, lubricants and the like.
2. DESCRIPTION OF THE RELATED ART
Air operated liquid spray dispenser assemblies typically include a spray head with a control valve, and a container releasably connected to the spray head. In preparation for use, the container is usually filled with liquid materials from a larger, bulk container, and the container is then coupled to the spray head which in turn is connected to an air hose. At the end of a spraying operation, the spray head is detached from the hose, and the container is detached from the spray head. Both the spray head and the container are then cleaned in preparation for the next spray operation.
Conventional spray heads have relatively small passageways, and thus are difficult to clean when used with certain liquid materials. In some instances, solvents may be used but are relatively expensive and somewhat hazardous. Moreover, such sprayers are not practical to use for liquids such as adhesives that cure and cannot be subsequently removed by solvents.
Recent developments in the art of air operated spray dispensers are described in U.S. Pat. Nos. 4,936,511 and 4,971,251, both of which are assigned to the assignee of the present invention. Such spray dispensers include a disposable, bag-like container that is non-releasably fixed to a spray nozzle assembly which, in turn, is adapted for detachable connection with a reusable air gun handle that includes a control valve. A rupturable barrier within the bag container prevents liquid materials from evaporating or leaking through the spray nozzle during transit. At the end of a work operation, the nozzle and attached bag container are removed from the handle and disposed, so that no cleaning is necessary.
However, shipping regulations in certain jurisdictions prevent or at least hinder shipping liquid materials in bag-like containers if the liquid materials include any solvents or flammable compositions. Moreover, there is a continuing interest in reducing the expenses associated with the spray nozzles and containers and the accompanying costs of filling the containers. As such, it is often prudent to consider the use of conventional liquid containers that are widely available and inexpensive to purchase and fill.
U.S. Pat. No. 4,804,144, dated Feb. 14, 1989, describes a spray dispenser apparatus that includes a disposable eductor assembly having a dip tube which extends into a screw top container. Both the eductor assembly and the container are detachably connected at separate locations to a tube structure which forms part of an air gun handle. Either the eductor assembly, the container, or both may be disconnected from the tube assembly for disposal when desired. The container includes an upper threaded tubular projection which is sealed by a disk having a scored center portion which may be punched out for passage of the dip tube.
However, the spray apparatus described in U.S. Pat. No. 4,804,144 is not entirely satisfactory when such a container is to be used as a shipping container and is labeled to identify the contents therein because of the possibility that the container may be refilled with another composition. In such circumstances, the container no longer correctly identifies the contents and may not sufficiently warn the operator of hazards associated with the contents (which is more of a potential problem if the apparatus is used by more than one person). Further, if the container is not sufficiently cleaned between uses, the new liquid contents may be contaminated or react with small amounts of the liquid materials originally packaged in the container.